Kosher food and drink is very well defined in the
Torah (see
Religious dietary laws and restraints). Classically, the only source of alcohol was that of
wine. For a wine
to be kosher, it must be certain (strict kashrus supervision of all steps of the wine making up until bottling) that no deities (such as
Dionysus) were invoked during the production. This was actually a problem back in ancient times (Christianity also made certain not to drink wine that had pagan deities invoked back then too), and the restriction remains today (kosher wine used as part of mass is not kosher). However, this aspect of kosher only applies to the
fruit of the vine - and not other forms of distilled spirits.
With wine it should be noted that for any Gentile to come in contact with Kosher wine would make the wine non-kosher (some of the wine may have been poured as an offering - this makes things complicated for non-Jewish cleaning help ("don't touch the wine rack - ever")). There is an exception
to this regarding boiled wine (labeled "Yayin Mevushal"). Traditionally, wine that has been boiled was not proper to be offered to an idol. Thus, for a non-Jew to come in contact with it, it would still be Kosher (may handle it, serve it - though still can't offer it to a god). Given today's delivery and retail (bars and restraunts too), almost all Kosher wine is boiled (and in the New York area, the distributor and retailer may be well be Jewish so the wine may not be boiled - care must be taken).
Passover also places a restraint upon things that are Kosher. While the items (and reasons for them) that are fit for Passover is a large body of material, of particular interest here is that of chometz. Chometz is the product of a grain sitting in water for eighteen minutes, or instantly in hot or salty water. Continuing on this, chometz products are forbidden to be owned by a Jew during passover - it must be sold to a gentile (in accordance with the Halacha) or destroyed. For a company to have a major stockholder or be owned by a Jew to have Bourbon, Whiskey, or Rye would make it non-Kosher, even if it was before. This extends to not only the owner of a store, but also the distributor. Thus, grain spirits sold by a Jewish owned store, distributed by a Jewish owned company, or produced by a Jewish-owned company if it was in the possession of any of them during passover. Typically, such a store would sell all of its chometz and would be closed during Passover. Alternately, if one really needs that Rye right after passover, purchasing it a non-Jew owned store would be acceptable.
Unflavored vodka is kosher (as are all grain spirits). However, once additional flavors are infused, it is possible that a non-kosher ingredient will spoil this. This is most common with adding a flavor of wine. The only flavored vodka that is explicitly stated as being kosher is that of Absolut.
Mescal and Tequila are kosher, unless there is a worm in it. The only insects that are kosher are locusts, though it has been pointed out that the species referred to in the Bible is not certain what it is today, and few people would eat them anyways. The 'worm' is actually the larva of a parasite that eats the Agave plants and is used as proof of the alcohol content - if the larva is in good shape, there is sufficient alcohol to keep it preserved. On the other hand, if the liquor has been watered down, the worm has gone bad.
Brandy, cognac, sherry, champagne, and vermouth
(a kosher martini is very dry) are all direct products
of wine and thus the wine must be kosher for the distilled
product to be kosher too.
Whiskey has some interesting labels when referring to blending. If it says "Blended Whiskeys" (plural) it often means that multiple whiskeys are blended together, in which case theres nothing funny and it would be kosher. However, if it is "Blended Whiskey" (singular) it often means that wine may have been blended with a whiskey in which case the wine must be kosher.
Blended scotch whiskeys has the same implications as whiskey itself. Malt Scotch, however, is malted in a sherry cask in which case, the sherry must have been kosher for the scotch to be kosher.
To confuse matters more, another source says that all scotch and whiskeys are acceptable. If in doubt, please ask a rabbi - I am not one (nor even Jewish, nor likely to drink scotch or whiskey).
Creme de Cassis is made with brandy, which must be kosher for the Creme de Cassis to be kosher. Likewise, Cointreau and Grand Marnier (citrus flavored) have a champagne and Cognac base, and thus would have to be made with kosher ingredients to be kosher. Furthermore, the Creme de Cassis is made with a cream - which may not be kosher.
The 'bean and kernel' spirits of Tia Maria, Kahlua are both kosher, being made with essentially coffee beans. (One site notes that Kahlua once had proper kosher supervision, but does not anymore. Another site states that both Kahlua and Tia Maria are Kosher, though Kahlua
cream is not)
Southern Comfort made in Ireland is kosher, while the one made in the United States is not. No reason for this is given just that that is explicitly stated.
An additional point to consider is that many mixed drinks are of questionable kosher nature. Such things as as the Bloody Mary which would contain tomato juice and Worcestershire sauce (may contain fish) are of to be thought about. Dairy creamers are also found in many
mixed drinks and thus needs to be considered (Chalav Akum or non-Jewish milk is prohibited by Rabbinic injunction; Rabbis fearned that gentiles may have mixed the milk of a non-kosher animal into the milk of the cow). Some drinks (for some reason I have yet to fathom) include beef bouillon which is rarely kosher.
Explicitly listed as 'not kosher':
http://www.kosherquest.org/html/General_Information_On_Alcohol.htm
http://www.kosherquest.org/bookhtml/WINES_AND_LIQUORS.htm
http://www.kosherconsumer.org/liquor.htm
http://www.kashrus.org/kosher/kosher_liquor.html